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Squatch Roofing cleaned and tuned up a three-tab asphalt shingle roof in Seattle, WA 98103 on September 24, 2026. The job started indoors: the August 28 inspection photographed a stained patch on a ceiling, then the attic, then a roof with moss growing in nearly every keyway and gaps at the corners of the chimney flashing. The recommendation was maintenance, not a new roof. On September 24 the crew sealed the chimney flashing, the exposed fasteners, and the plumbing vent, then spread zinc sulphate across the slopes.
| Location | Seattle, WA 98103 |
|---|---|
| Service | Roof cleaning (zinc sulphate moss treatment) with a roof tune-up |
| Property | Home with a gable roof, a brick chimney, a plumbing vent, and a box vent |
| Roof size | Priced on the small tune-up tier, which covers roofs up to 20 squares; the exact square count is not recorded |
| Inspection | August 28, 2026: interior ceiling, attic, roof surface, chimney, and penetrations; 17 photos on file |
| Existing roof | Three-tab asphalt shingles; moss rooted in the keyways across the slopes, with loose clumps on the shingle faces |
| Tune-up work | Chimney flashing corners and fasteners sealed, exposed shingle fasteners sealed, plumbing vent flashing sealed with a rubber collar on the pipe |
| Moss treatment | Zinc sulphate powder applied across the slopes and along the ridge, September 24, 2026 |
| Project duration | One visit, September 24, 2026 |
| Project investment range | $600 to $1,000 |
What Squatch Found on the Inspection
The inspection on August 28, 2026 produced 17 photos, and the first two were taken inside the house. They show a small stained patch on a ceiling near an exterior wall. From there the inspector went into the attic, then onto the roof.
- Ceiling: one stained patch, photographed from two angles.
- Attic: board decking over rafters with loose blown insulation between them, photographed with a flashlight. The attic photos do not show the source of the ceiling stain, and the job file does not record one.
- Moss: a line of moss in nearly every keyway between the three-tab shingles, with loose clumps sitting on the shingle faces.
- Chimney: the step and apron flashing at the brick chimney had open corners where the metal pieces met, with old sealant at the joints.
- Penetrations: the plumbing vent’s flashing had moss growing at its edges, and a box vent sat in the same mossy field.
What It Meant and What We Recommended
A ceiling stain can make a homeowner assume the worst. What the inspection photographed on the roof was not a worn-out shingle field. It was moss in the keyways, where it holds water against the shingles, and a handful of places where the roof’s seals were open or aging: the chimney flashing corners, exposed fastener heads, and the plumbing vent. Those are tune-up items.
Squatch quoted two line items: a roof tune-up at the small tier (roofs up to 20 squares) and a zinc sulphate roof cleaning priced per square. No replacement or larger repair was quoted. The homeowner approved it, and the work was scheduled for September 24.
How the Project Was Completed
Everything happened in one visit on September 24, 2026, and the crew’s 21 photos from that day fall into two groups.
The tune-up came first. The crew sealed exposed fastener heads in the shingle field, sealed the corners of the chimney flashing and the fasteners along its base, and sealed the plumbing vent flashing, where the pipe now carries a rubber collar at its base. In the close-up photos from this stage, the keyways that were full of moss on August 28 are clear.
Then the zinc sulphate. The crew spread zinc sulphate powder across the slopes and along the ridge. It is applied dry and left on the roof, which is why the completion photos show white streaks down every slope. The powder is not a rinse. Rain dissolves it over the following weeks and carries it down the shingles.
The Finished Result
The completion photos show the keyways free of the moss lines from August 28, zinc sulphate across every slope and the ridge, the chimney flashing corners sealed, the plumbing vent collared and sealed, and the exposed fasteners covered. The job closed out the same day.
What This Cleaning and Tune-Up Cost
Project investment range: $600 to $1,000. This range reflects the scope of this completed project and is not a current quote. It is anchored on the final invoice total, which includes Washington sales tax.
Two things set this price. The roof falls on the small tune-up tier (up to 20 squares), and the zinc sulphate cleaning is priced per square, so a larger roof costs more on both lines. The scope was also limited to sealing and moss control. A flashing replacement at the chimney or a leak repair would have been a different line item and a different number.
What Homeowners With Similar Roofs Should Know
A ceiling stain is where the inspection starts, not the verdict. This inspection began at the stain and worked up through the attic to the roof. What the roof showed was moss and a few open seals, and the recommendation matched that: a tune-up and moss treatment for under $1,000 rather than a new roof.
Watch the corners of the chimney flashing. On this roof the flashing was intact but open where the metal pieces met, which is the kind of gap a tune-up closes with sealant.
Zinc sulphate looks messy on day one. The white streaks in the completion photos are the treatment doing its job, not residue left behind. For a heavier moss or debris load, Squatch uses a different process; this SasWash treatment on another Seattle three-tab roof shows it.
Related questions
How much did this roof cleaning and tune-up in Seattle cost?
The project investment range for this completed job was $600 to $1,000 for a small-tier roof tune-up and a zinc sulphate moss treatment on a three-tab shingle roof. The range reflects this project’s scope and is not a current quote.
What does a roof tune-up include?
On this job it meant sealing the corners and fasteners of the chimney flashing, sealing exposed fastener heads in the shingle field, and sealing the plumbing vent flashing, with a rubber collar on the pipe. The crew photographed each item on September 24, 2026.
Did the ceiling stain mean the roof needed replacing?
Not on this house. The inspection photographed the stain, the attic, and the roof, and the roof showed moss in the keyways and a few open seals rather than a failing shingle field. Squatch quoted a tune-up and moss treatment only. The job file does not record the cause of the stain.
Why is the roof white after the zinc sulphate treatment?
Zinc sulphate is spread as a dry powder and left on the roof. The white streaks in the completion photos are the powder itself, which rain dissolves and carries down the shingles over the following weeks.
How long did the work take?
One visit. The inspection was August 28, 2026, and the tune-up and zinc sulphate treatment were both completed on September 24, 2026, when the job closed.
Have a roof with similar symptoms?
If you have a stain on a ceiling or moss filling the seams of your shingles, Squatch Roofing can run a free 21-point inspection, show you the photos, and tell you whether a roof cleaning and tune-up is all it needs. Squatch serves Seattle, the Eastside, and the greater Seattle area. Schedule an inspection or call (425) 292-8327.
This project documentation was prepared by Squatch Roofing from the job records and photos from our crew, September 2026. Technical review by Ben Metsker, Manager, Squatch Roofing.
